dishonorable kills

[fisherman]

im pretty new to this game still and have a question. is a dishonorable kill bad to get? i mean the name itself implies its bad to get a "dishonorable kill" however im not sure if this is the case. is got a dk from killing a civilian in the barrens and im wondering if that was bad to do/can it ever go away/ does it even freakin matter. also i was just bored and went exploring and ended up into the barrens i believe (im alliance) and got to the front door of orgrimmar before getting owned. however i couldnt attack anyone human player unless they attacked me first. is this normal?

actually i got a dk from killing a civilian in the barrens and now im wondering if this is shitty to have on my character because i could alsways start over. (im not a high lvl)

thanks for your time.